Portion of a sole bottom surface



FIG. 1 is a bottom plan view of a portion of a sole bottom surface showing my new design;

FIG. 2 is a cross-sectional profile view taken generally along the line 2--2 of FIG. 1;

FIG. 3 is a cross-sectional profile view taken generally along the line 3--3 of FIG. 1;

FIG. 4 is a cross-sectional profile view taken generally along the line 4--4 of FIG. 1;

FIG. 5 is a cross sectional profile view taken generally along the line 5--5 of FIG. 1; and,

FIG. 6 is a perspective view of the portion of a sole bottom surface shown FIG. 1. 

The ornamental design for a portion of a sole bottom surface, as shown and described. 